1. Field of the Invention
This invention relates to an apparatus and process for obtaining a percentge aliquot of serial liquid samples having a constant or variable volume. Aliquoting of serial liquid samples is desired for many testing routines to provide a mixed fraction of each of a series of samples for a single test routine.
2. Description of the Prior Art
It is frequently desirable for plant quality control or for other testing procedures to obtain a single fractional amount of a series of liquid samples. For example, the laboratory analysis of urine specimens is often a standard procedure in the diagnosis and treatment of various human diseases and ailments, as well as to determine the overall well-being of human bodily functions or the determination of improper functioning of one or more of the processes of the body, organs, glands or systems. The collection and analysis of urine specimens is practiced universally throughout the health delivery industry. While the medical profession has developed and adopted a variety of sophisticated methods and test procedures in the analysis and reporting of data of urine specimens, the routine collection methods have not improved. Many medical analyses require the patient to collect all urine excreted during a 24-hour period. The present method of such collection requires collecting each sample in a container and then transferring each sample to a sufficiently large container to accommodate the entire 24-hour series of samples or directly adding each sample to the large container. Therefore, the large container must be maintained in proximity to the person being sampled for the entire 24-hour period which is often inconvenient since 24-hour urine samples are frequently needed from active persons engaging in normal activities. To say the least, this method of sample collection of serial samples is inconvenient for the patient throughout the 24-hour day. Frequently, hydrochloric acid or other preservative must be used in connection with maintaining the samples over the 24-hour period and the patient must be cautioned about touching the liquid preservative. In other instances, the samples must be kept cool to prevent growth of bacteria and the patient may be required to refrigerate all of the samples collected over the 24-hour period. The large container must then be returned to the doctor's office, hospital or other sampling center, where laboratory tests are conducted. Normally, the laboratory tests require only about 1 to about 3 percent of the total collection volume. These small amounts are measured and removed from the large serial collection volume and the remainder of the collection volume is then discarded.
A further problem with current liquid sampling techniques as described above has been that in practice, more than one 24-hour specimen is often required of a patient, and frequently the different samples are required to be subjected to different or no preservatives. In these cases, it is the present practice to perform sequential sampling, that is repeat the process, which has the disadvantage that the second tests are performed on samples which may be very different from the first tests due to various bodily functions and thus the test results are not validly comparable.